Easy Goer, one of the best American racehorses of the last decade, was retired yesterday.

The announcement came as a surprise, for Easy Goer had been training for a long-awaited rematch with archrival Sunday Silence at Arlington Park in Chicago next month.

However, the 4-year-old reportedly suffered an injury during his training at Belmont Park. Trainer Shug McGaughey wasn't available for comment, but assistant trainer Buzzy Tenney said: "He's got a little chip on his sesamoid. It's on the right front, on the inside. He's not in any real distress, but he can't train with the chip."

Tenney said the bone chip was discovered Sunday: "He galloped in the morning, and he was a little ouchy in the stall that afternoon. So we went ahead and X-rayed him."

This announcement was a disappointing and anticlimactic end to a career that had been marked by many disappointments. As brilliant as Easy Goer was, his legion of fans will always think he could and should have done better.

Easy Goer had a regal pedigree -- by Alydar out of the champion mare Relaxing. He was owned by one of America's dynastic racing stables, and managed by an astute young trainer. In his first few races as a 2-year-old during the summer of 1988 he displayed as much precocity and promise as any racehorse since Secretariat. He went on to be voted the champion of his age group, even though he lost the Breeders' Cup Juvenile on a muddy track, a defeat that presaged a pattern of failure in the big ones.

After dominating weak competition early in his 3-year-old season, Easy Goer was hailed as a potential Triple Crown winner. But that was before the racing world knew how good Sunday Silence was. The California colt scored an upset over a muddy track in the Kentucky Derby, and when Easy Goer's fans blamed the track condition, Sunday Silence came back to win the Preakness, after an electrifying head-and-head battle through the stretch. That Preakness was voted the "race of the decade" in a national poll.

Easy Goer finally gained revenge against Sunday Silence in the Belmont Stakes, winning by eight lengths in the time of 2:26 for 1 1/2 miles. It was the best performance of Easy Goer's career, his best claim to greatness, and it was seemingly the proof that Easy Goer was a better horse than Sunday Silence. However, Sunday Silence won their memorable showdown in the Breeders' Cup Classic by a neck, winning all of the year-end honors and whetting the appetites of racing fans for a rematch in 1990.

However, the 4-year-old Easy Goer never looked like the same imposing animal he had the year before. He lost his one serious test, the Metropolitan Handicap, with the only inexplicably dull performance of his career; perhaps he was suffering physical problems then too. He did bow out a winner, however, by beating a weak field in the July 4 Suburban Handicap at Belmont, and he will go to stud (presumably at Claiborne Farm in Lexington, Ky.) with a glittering record.

Easy Goer made 20 starts in his career, winning 14 and finishing in the money in all 20. He won many of America's most prestigious stakes races, including the Champagne, Travers, Woodward and Jockey Club Gold Cup. He amassed earnings of $4,873,770.

But his statistical record had some conspicuous blemishes. Easy Goer seemed to benefit from a home-track advantage; his record in major stakes outside New York was zero for four. Against Sunday Silence, the one acknowledged great horse he faced, he was one for four.

If a couple of photo finishes in their rivalry had gone the other way, Easy Goer would have been acclaimed as horse of the decade, and his retirement would seem an even greater loss to the sport.